The prior art includes drainage hoses or drain for medical use, such as prophylactic, surgical, or post-operative use. Within this wide range of medical drainage hoses, there are usually two types: a closed-type and an open-type.
If a drain hose has one or more internal channels, that can cause occlusion or blockage due to the fluid being extracted, such as, for example, blood coagulation or deposition of other type of fluids. In some cases it is desirable that a drain hose is formed by more than one channel or canal. Therefore, in case of occlusion occurrence, the other canals may maintain fluid communication with the drainage area. Likewise, closed-type suction drainage systems are not exclusively limited for extracting fluids. At the same time, said systems may serve for introducing some kind of solution into the drainage area. For example, for saline spraying or flushing, it is often desired to have more than one channel or canal. A drain with external channels can also represent a risk for clogging or blocking, meaning that the light beam is occluded, but less likely than in the first ones.
Moreover, during usage, these drainage hoses are subjected to a variety of inner pressures inside the body, such as the oozing fluid pressure or the pressure resulting from the masses of skin or other tissues where the drain passes through. Based on the above, it is desired that a drain or drainage hose be provided with a strong and resistant structure for use in the medical field. To further illustrate this point, in case that a drainage hose collapses inside the body, it will block the fluid drainage path. Likewise, it is also desired to prevent the collapse of the structure or occlusion of a suction drainage system drainage hose (which can occur due to the suction system pressure internally “sucking” the hose).
Furthermore, another desirable feature in a drain refers to the extracting capacity of the fluids in the lowest possible time, so that the drain stay as short as possible. Thus, it is desired that a drain has a configuration that optimizes the flowing surface.
When finalizing usage, the drain is extracted from the patient's body. During the extraction procedure, the drain must be folded or rotated in a clockwise direction and backwards over its axis a few times. Therefore, the drain can have a symmetrical shape that facilitates the extraction procedure.
As has been mentioned in the preceding paragraphs, all of the above features should be present in the drainage hoses manufactured nowadays. However, there is prior art indicating that not every drain meets with all the desirable features. The following are some of these documents and its disadvantages currently.
The prior art describes various drainage systems and catheters. For example, patent applications WO2010060227, GB2422410, and MX2008014160 describe drainage hoses with more than one internal canal. Any of these inventions have the risk of fluid flow obstruction, but in addition, the asymmetrical shape of the outer hinders the extraction procedure described above.
Moreover, the US Patent Application No. US20080319419 describes a drain with two internal canals that run symmetrically arranged. Additionally, the exterior of this drain is circular so it facilitates extraction operations. However, its tubular configuration, where both canals are separated by a partition, does not provide this drain with sufficient structural strength to prevent collapse.
The same occurs for other drainage hoses or catheters which run inside more than two internal canals, as disclosed in the international application publication no. WO2009120871, US application publication no. US20100049147, Japanese patent application no. JP2007202901, as well as U.S. Pat. Nos. 6,485,481, 5,486,159, 5,451,206, and 5,378,230. While all these drainage hoses have various internal canals, and a circular outer shape that facilitates the removal thereof, the configurations of these structures are not optimal for preventing collapse or providing adequate flow of the extracting fluid. Moreover, for being a closed-type drainage hoses, all of them have a high risk of inner clogging/obstruction during usage. The same disadvantages are also true for US patent application no. US20050215949 whose external shape is slightly elliptical.
There are also a variety of drainage systems having drain hoses with canals and outer grooves, which minimize the risk of clogging of the canal. However, some of these hose designs do not allow flow optimization and do not always have an adequate structural strength to support compression due to the surrounding organs and tissue.
Also, there are some mixed drainage hoses that have both external canals and internal conduits for fluid communication. An example of this type of drain or catheter is described in the international publication no. WO2002/030489 for peritoneal dialysis usage, where some embodiments have both external canals and internal conduits. However, the configuration of this type of catheter/drain does not allow flow optimization and does not provide structural strength to the catheter/drain.
Some relevant art may be found in the international publications nos. WO2001/036021 and WO2007/082157, as well as the catheter/drain commonly known as Blake, a surgical and medical industry standard, originally described in U.S. Pat. No. 4,398,910.
International application WO2001/036021 describes a drain that has a symmetrical configuration of multiple ducts and lumen. In the preferred first embodiment, the transversal drain configuration is a cross shape comprising four ducts and four lumens, conforming a mixed system wherein the ducts have outer fluid communication and the lumens have inner fluid communication. The disadvantage of this configuration is that the inner lumens have the same risk of clogging than the closed-type drain described above. Moreover, the '021 application also illustrates a configuration where some portals maintain fluid communication between ducts and lumens. This causes even more blockage risk areas, such as the circumferential edges of the lumens. Additionally, the formation of these portals in the lumens walls can significantly weaken the structural strength of the drain, increasing the collapse risk. Also, the cross-shaped configuration does not always provide the best configuration before radial forces; a triangular configuration works better for such purposes.
International application WO2007/082157 describes a triangular-configuration drain for medical applications and uses. The advantages of this drain are a configuration having three lumens or drainage canals, and outer walls curved in a substantially circular manner to avoid difficulties during drain removal from a patient. However, due to the fact that the drain circumferential walls extend in clockwise direction, there is a high risk that could negatively affect the drain removal actions from the patient, wherein said drain is rotated. That is, if during the removal action the rotation is taken in the wrong direction, the patient may experience pain and complications. In addition, the drain core comprises an internal passage with the above-described high clogging or occlusion risks.
Finally, U.S. Pat. No. 4,398,910 corresponds to the catheter known in the medical field as “Blake.” This catheter corresponds to a drain conformed by four symmetrical distributed lumens. While it may be the case that the Blake drain can drain fluids properly with low occlusion risk of the light beam and good structural strength, the effective flow area, as well as structural strength, of the Blake catheter can be improved. As mentioned, the Blake drain is now commonly used in the medical-surgical industry. However, the disadvantages that this design keeps with respect to aspects of the present invention will be demonstrated later in the comparative analysis that accompanied this description.
Therefore, a new drain design that overcomes the above-mentioned disadvantages of the prior art is desired.